This invention pertains to a two-stage screw compressor. A screw compressor of this type is known from DE 299 22 878 U1, among other documents. Reference is made to the disclosure of this document in its entirety.
In this prior art screw compressor, each of the two compressor stages, which jut out from the gear housing parallel to one another, is enclosed by its own coolant housing that is connected to the coolant circuit or coolant sump through its own connection. Because of the space requirements of the coolant housings of the two compressor stages mentioned, the design of this prior art screw compressor is not particularly compact.
A prior art screw compressor is known from U.S. Pat. No. 4,174,196 that has two compressor stages whose compressor housings are arranged parallel to one another and are enclosed by a common inner housing. The inner housing is enclosed by a concentric outer housing and the annulus between the inner and outer housing is subdivided into chambers through which a coolant flows in order to cool tube bundles located within the chambers through which the compressed gas flows. A first coolant stream cools the compressed gas from the first compressor stage, and a second coolant cools the compressed gas from the second compressor stage. The coolant has essentially no direct cooling effect on the rotor housings of the two compressor stages.